Willy Ley was an American science writer born in Berlin, Germany who was a life-long space advocate who helped popularize rocketry and spaceflight in both Germany and the United States. In 1935, he fled Nazi Germany for Great Britain and later the US.

He was an avid reader of SF, and began publishing scientific articles in the prozines, starting with "The Dawn of the Conquest of Space" in the March 1937 issue of Astounding. He had a regular science column in Galaxy from its first issue until his death. He was a fan as well, attending conventions, and was a regular on convention programs.

Growing up in Germany, Ley studied astronomy, physics, zoology, and paleontology and became interested in spaceflight after reading Hermann Oberth's book and became one of the first members of Germany's amateur rocket group, and acted as a consultant on Fritz Lang's film Frau im Mond ("Woman in the Moon").

His works from the 1950s and '60s are regarded as classics of popular science and include: